Investigation of Dummy Response and Restraint Configuration Factors Associated with Upper Spinal Cord Injury in a Forward-Facing Child Restraint

Dummy response and restraint configuration factors associated with a known child injury environment were investigated using a spinal-cord injury accident case, a full-scale reconstruction, and sled simulations. The work is one of several studies undertaken in association with the International Task Force on Child Restraining Systems to support the development of improved neck injury criteria and restraint systems for young children. A two-vehicle crash involving a restrained child occupant was investigated in detail and reconstructed in full-scale at the Transport Canada Motor Vehicle Test Centre using the CRABI 6-Month dummy. Vehicle damage and crush characteristics closely resembled that of the case vehicles. Dummy instrumentation included head and chest accelerometers and upper and lower neck transducers. The case occupant had been facing forward and had sustained a contusion of the spinal cord at T2 that resulted in paraplegia. The crash environment was then simulated in a more simplified manner on the UMTRI impact sled using the same dummy. Test conditions were adjusted until the dummy responses were similar to those obtained in the original reconstruction. Other parameters having to do with restraint effectiveness, including child restraint back angle, harness tightness, and tether attachment, were then varied, and the dummy response measures were compared. Finally, a series of tests was conducted using a current model child restraint and variations of the same parameters to compare with the earlier tests. Results of these test series indicate that variations in forward-facing child restraint system configurations thought to influence neck loading have a minimal effect for this size dummy. Further investigations with larger child dummies are needed, and the available solution of rear-facing restraints for the smaller children is reinforced.